It is considered that when uric acid content in blood exceeds a certain limit, uric acid would deposit as sodium urate and deposition of sodium urate on the articular cavity or kidney would cause gout, renal disorders or vascular disorders. As known causes of hyperuricemia, there are reduced excretion of uric acid, excessive production of uric acid, abnormality of purine metabolizing enzyme, disease associated with hematopoietic organ or renal disorders, administration of chemicals such as pyrazinamide or thiazide, and the like. Irrespective of any cause, continuous hyperuricemia results in incidence of gout in most cases and if further worsened, leads to renal insufficiency or cardiovascular disorders. Further in the case of children, a disease called Lesch-Nyhan syndrome which is caused by excessive production of uric acid due to enzyme abnormality is known.
Since these diseases are caused by high blood concentration of uric acid, drugs having an activity of excreting uric acid, for example, probenecid, sulfinpyrazone or benzbromarone have been used for the treatment of hyperuricemia.
The present invention provides compounds having excellent properties as agents for the treatment of hyperuricemia.